1. Field of the Invention
The present invention relates to the technical field of a peer-to-peer (P2P) communication system having a plurality of node devices capable of performing communication with each other via a network.
2. Discussion of the Related Art
A content distributed-storage system for storing content data in a plurality of node devices so as to be distributed (distributed-storage) in a peer-to-peer communication system of this kind is known. By the system, fault-tolerance and access dispersibility is increased. The locations of content data distribution-stored can be efficiently retrieved by using, for example, a distributed hash table (hereinbelow, DHT) disclosed in Patent Document 1. The DHT is stored in each of node devices. In the DHT, node information (including, for example, the IP address and the port number) indicative of a plurality of node devices to which various messages are to be transferred is registered.
When it is demanded to obtain desired content data, a node device participating in a content distributed-storage system transmits a message (query) for retrieving (finding) the location of the content data to another node device. The message is transferred toward a node device that manages the location of the content data via a plurality of relay node devices in accordance with the DHT. The node device obtains node information from the managing node device to which the message is finally transferred. With the node information, the node device which has transmitted the message can request for the content data to a node device that stores the content data related to the retrieval and receive the content data provided.
Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 2006-197400